1016 Origin DNS Error when proxy enabled, otherwise working

I’ve added a single A record for www.example.com to point to an IP address at DigitalOcean. The IP resolves and serves a web page. The domain www.example.com resolves and serves the same web page. When I turn on Cloudflare proxy, I get a 1016 Origin DNS Error. I’ve done a lot of searching thus far and can’t find anything to resolve this. What additional details can I share to get any insight into this? Thanks to anyone that can help.